H-B,
A tutor is never overkill if a) you are serious about improving, and b) you want to maximize the speed at which that improvement will occur. The chief functions of a tutor are to a) work with you to identify your most important weakness, and b) put together a training/mentoring program to address those weaknesses. (And, perhaps, to encourage us when we stumble in our efforts.)
Of course, this can be done on one's own, but honest introspection is not easy and building a custom improvement plan may not be something all of us are prepared to do. Remember, it's not the playing strength of the coach that counts most; it's the coaching strength. That said, one is often best helped by a coach with a playing strength of 400+ rating points higher than your current strength. (I've had a GM-level coach and a master-level coach before ... the master-level coach was a far better coach. Just one person's experience.)
And remember to be patient, adults learning differently (and usually a bit slower) than young folk do.
I encourage you to take that step, if you meet the criteria I mentioned above.
Best wishes.
Me:
Fourty-something casual player who has over the years played a couple of club players and is likely in the 1500+ range that my online chess rating would suggest.
I want to get better, of course. But I am considering entering OTB tournaments. Would a tutor be overkill for me?